Explanation of Superfluidity Using the Berry Connection for Many-Body Wave Functions

TL;DR

This paper unifies superfluidity and superconductivity phenomena through a collective mode derived from the Berry connection in many-body wave functions, emphasizing its fundamental role over electron pairing.

Contribution

It introduces a collective mode from the Berry connection as a unifying explanation for superfluidity and superconductivity, highlighting its fundamental importance.

Findings

Superfluidity and superconductivity are linked via a Berry connection-derived collective mode.

The collective mode's stabilization is key to superfluidity and superconductivity.

This approach suggests a fundamental origin of superconductivity beyond electron pairing.

Abstract

We show that two phenomena of superfluidity, superfluidity of weakly interacting bosons and superconductivity of the BCS model, are unified using the collective mode arising from the Berry connection for many-body wave functions. The superfluidity is attributed to the presence of this mode, which is stabilized by the interaction between particles that causes fluctuations of the number of particles participating in it. It is suggested that the existence of this collective mode and its stabilization is more fundamental to the occurrence of superconductivity than the electron-pair formation.